1. Field of the Invention
The present invention relates to a photo diode of an optical pick-up device, and more particularly, to an apparatus for and method of controlling sensitivity of a photo diode using a digital potentiometer.
2. Description of Related Art
An optical pick-up device is used for reading, writing and deleting data from an optical disk using light emitted from a laser diode (LD). A monitor photo diode (PD), called also a front photo diode (FPD), detects optical power emitted from the laser diode of the optical pick-up device and feeds back a detected result to an optical power controller. The optical power controller controls the optical power of the laser diode with optical power information fed back from the monitor photo diode.
With the development of high performance optical disk drives (ODD), it is more important to control the sensitivity of the photo diode. Easy and exact control of the sensitivity greatly contribute to improvement in performance of ODDs.
A conventional optical pick-up device has a 500-Ohm or 2.2K-Ohm variable resistor, i.e., manual rotary resistor, in order to control the sensitivity of the photo diode. However, because of errors and loss of control time caused by an operator's direct control, it is hard to control the sensitivity of the photodiode with such variable resistors.